<!DOCTYPE html>
<html>
  <style>
    input[type="color"] {
      -moz-appearance: button;
    }
    input[type="color"]::-moz-color-swatch {
      margin-top: 3px;
      margin-bottom: 3px;
    }
  </style>
  <body>
    <input type="color" />
  </body>
